Median Motor Conduction Velocity Research Articles

Relationship of obesity indices with clinical severity and nerve conduction studies in females presenting with median nerve compression neuropathy at the wrist.

Carpal tunnel syndrome (CTS) is considered to be one of the most common peripheral nerve disorders with female preponderance which significantly reduces work efficacy and needs further research on its preventable factors, especially obesity. We studied the effects of obesity indices on Phalen's test duration and median nerve conduction study (NCS) parameters in patients presenting with CTS. We examined 229 female patients presenting with clinical features of CTS. Clinical examinations including Phalen's test, median NCSs, and body composition were evaluated. Obesity indices and electrophysiological parameters were compared. There were significant associations of both body mass index (BMI) degrees and body fat percent (BF%) with clinical and NCS parameters with a linear relationship. BF% and BMI were strongly negatively correlated with Phalen's test duration (BF%; r = -0.334, BMI; r = -0.270 P = 0.001). On the other hand, BF% and BMI were positively correlated with median distal latency (BF%; r = 0.338, BMI; r = 0.372, P value = 0.001), M-latency (BF%; r = 0.264, BMI; r = 0.285, P = 0.001), median motor conduction velocity (MMCV) (BF%; r = 0.119, P = 0.072, BMI; r = 0.173, P = 0.009), median sensory conduction velocity (MSCV) (BF%; r = -0.195, P = 0.003, BMI; r = 0.327, P = 0.001), and sensory nerve action potential (SNAP amplitude) (BF%; r = -.239, BMI; r = -0.350, P = 0.001). Nerve conduction parameters are significantly affected by obesity degree defined by BMI and BF%. Therefore, combining BMI and BF% assessments gives more clinical information regarding CTS severity and management. The true predictive value of these indices needs to be elucidated further.

Correlation Between Fibrinogen/Albumin and Diabetic Peripheral Neuropathy.

This study aimed to examine the correlation between fibrinogen/albumin (FAR) and diabetic peripheral neuropathy (DPN). A total of 342 patients were included and categorized into either the DPN group or the Non-DPN (NDPN) group based on their DPN status. The FAR index was determined by calculating the ratio of fibrinogen (FIB) to serum albumin (ALB), multiplied by 100. The participants were then divided into a High-FAR group and a Low-FAR group using the median FAR value as the threshold. Neurophysiological data were collected from the participants, which included motor conduction velocity (MCV) and sensory conduction velocity (SCV). The DPN group displayed higher FAR levels [(DPN vs NDPN:6.72 (5.89,7.74) vs 5.94±1.14], in addition to slower SCV and MCV data compared to the NDPN group. The high FAR group had a higher prevalence of DPN (78.9% vs 55.6%) (P<0.05). There was a negative correlation between FAR and NCV, including bilateral median nerve SCV, left ulnar nerve SCV, bilateral median nerve MCV, bilateral common peroneal nerve MCV, bilateral tibial nerve MCV, and left ulnar nerve MCV. FAR was revealed to be an independent risk factor for the development of DPN in patients and demonstrated a greater predictive value for DPN development in Type 2 diabetes mellitus (T2DM) compared with FIB, HbA1c. The results suggest that monitoring FAR levels in patients with T2DM could identify those at higher risk for developing DPN, making the FAR index a valuable predictor of DPN development. Furthermore, since FAR has an inverse relationship with NCV, it stands to reason that high FAR levels may indicate nerve damage and slower conduction velocities. Thus, managing FAR could prove beneficial in both preventing and delaying the onset of DPN in T2DM patients.

Body mass index and carpal tunnel syndrome: A case-control study.

To investigate the electrophysiological characteristics of carpal tunnel syndrome (CTS) and to evaluate the relationship between electrophysiological indexes and body mass index (BMI). In the analysis of 153 hospitalized patients with CTS, the median motor conduction velocity, motor conduction amplitude, motor conduction latency, sensor conduction velocity, sensor conduction amplitude and median sensory latency were analyzed. BMI was calculated. Total 171 healthy individuals were selected as control group. According to Guidelines for Prevention and Control of Overweight and Obesity in Chinese Adults, patients were divided into groups A, B and C. Patients with BMI (kg/m2) <24 were classified into group A; those with 24 ≤ BMI < 28 were regarded as overweight and classified into group B; and those with BMI ≥ 28 were regarded as obese and classified into group C. The BMI of CTS patients was significantly higher than that of healthy individuals (P < .05). For the sensory nerve, with the increase of BMI, the incubation period was gradually prolonged and the conduction velocity gradually decreases (P < .05). In terms of motor latency, with an increase in BMI, the latency showed a trend of first decreasing and then increasing, while the conduction velocity showed a trend of first increasing and then decreasing (P < .05). Electrophysiological examination plays an important supporting role in the diagnosis of CTS. BMI is positively correlated with the degree of CTS injury to a certain extent. Weight loss can effectively prevent the occurrence of CTS and slow the progression of nerve damage in CTS patients.

AĞIR KARPAL TÜNEL SENDROMU İÇİN RİSK FAKTÖRLERİNİN İNCELENMESİ - EV HANIMLIĞI BİR RİSK Mİ?

Carpal tunnel syndrome (CTS) is the most common entrapment neuropathy. In this study, risk factors of severe CTS were examined. This study was conducted on 227 patients diagnosed with CTS in EMG laboratuary. The criteria of American Academy of Electrodiagnostic Medicine was used as the diagnosis for CTS. All patients were examined for bilateral median and ulnar motor and sensory peak latency, amplitude and conduction velocities. The patients were classified into 4 groups electrophysiologically; Normal, Light, Medium, Severe. Electrophysiological classification was compared with the identified risk factors. The mean age of the patients was 51.04±13.37 (min=18-max=83). Severe CTS cases in both hands were higher in housewives. Housewifery increased the risk of severe CTS in the right and left hand by 2.74 and 2.23 times, respectively. In addition, obesity increased the risk of severe CTS in the right and left hand by 5.10-4.40, presence of lateral epicondylitis was 2.73-4.19 and medial epicondylitis was 4.39-4.93, respectively. Hand dominancy was increased the risk of severe CTS by 6.88 times for the left hand and 1.15 times for the right hand. Otherwise in multivariate analyse of left hand results, obesity increase the risk of severe CTS by 3.34, left hand dominancy 7.83 times, chronic disease 2.62 times, and for the right hand being a housewife increases the risk by 2.14, obesity 4.68 times and medial epicondylitis 6.40 times. This study put forth that being a housewife, obesity, dominant hand, presence of lateral or medial epicondylitis are the risk factors of severe CTS.

Effect of estrogen and progesterone on nerve conduction studies during ovarian cycle.

Objectives This study aims to investigate the effects of estrogen and progesterone on nerve conduction studies (NCSs) in three different hormonal phases of the ovarian cycle. Patients and methods Between April 2008 and July 2008, a total of 40 healthy volunteer women (mean age: 24.1±5.1 years; range 21 to 43 years) with regular menstrual cycles were included in this prospective study. The participants were regularly menstruating for at least one year, without any hormonal disease and without taking any medication that could lead to hormonal dysregulation. Motor and sensory conduction velocities, amplitudes, and distal latencies were analyzed at the dominant extremities within the early follicular phase (EFP), late follicular phase (LFP), and the midluteal phase (MLP). Results Except for the median nerve motor conduction velocity (MCV), there were no statistically significant differences between the peripheral NCS results in the three ovarian cycle phases (p=0.033). After adjusting for multiple comparisons, a significant difference was found between the EFP and LFP (p=0.004). Conclusion Our study results showed that only median nerve MCV was affected in the menstrual cycle. However, this would be an incidental finding, or an increased sensibility of the median nerve motor fibers to ovarian steroids by an unknown mechanism. Further studies are warranted.

Correlation Between Hemoglobin Glycosylation Index and Nerve Conduction Velocity in Patients with Type 2 Diabetes Mellitus.

ObjectiveThis study aimed to investigate the relationship between hemoglobin glycation variation index (HGI) and peripheral nerve conduction velocity (NCV) in patients with type 2 diabetes mellitus (T2DM).Materials and MethodsThis is a cross-sectional study, including 324 patients with T2DM were included in this study. Basic information and blood indicators were collected. The motor conduction velocities (MCV) of the bilateral ulnar nerve, median nerve, and common peroneal nerve, and the sensory conduction velocities (SCV) of the ulnar nerve, median nerve, and superficial peroneal nerve were measured. The patients were divided into two groups according to the NCV: normal nerve conduction group (NCVN group) and abnormal nerve conduction group (NCVA group). When the NCV is less than the specific normal value, the patients were divided into the NCVA group. HGI was calculated as the difference between the measured and predicted values of glycosylated hemoglobin (HbA1c) using the linear relationship between HbA1c level and fasting plasma glucose levels. At last, all study participants were divided into High HGI and Low HGI groups using the median of HGI as the boundary. The study also analyzed the correlation between HGI and NCV.ResultsCompared to the NCVN group, the HGI levels of the NCVA group were higher (P < 0.001). The prevalence of NCVA in the high HGI group was higher than that in the low HGI group (P = 0.004). HGI was negatively correlated with bilateral ulnar nerve MCV, bilateral median nerve MCV, bilateral common peroneal nerve MCV, bilateral median nerve SCV and left superficial peroneal nerve SCV, and the correlation still existed after adjusting for confounding factors.ConclusionThis study found that HGI is inversely associated with NCV in patients with T2DM, and this correlation is higher between HGI and MCV of peripheral nerve.

Correlation Between Thioredoxin-Interacting Protein and Nerve Conduction Velocity in Patients With Type 2 Diabetes Mellitus

Aims: To investigate the correlation between thioredoxin-interacting protein (TXNIP) and peripheral nerve conduction velocity (NCV) in patients with type 2 diabetes mellitus.Methods: In total, 338 patients with type 2 diabetes mellitus (T2DM) were included in this study. We collected the clinical data and measured the motor conduction velocities of the bilateral ulnar nerve, median nerve, tibial nerve, and common peroneal nerve, and the sensory conduction velocities of the ulnar nerve, median nerve, sural nerve, and superficial peroneal nerve. According to the results, the patients were divided into two groups: normal peripheral nerve conduction group (NCVN group) and abnormal peripheral nerve conduction group (NCVA group). The two groups were then compared in terms of the conventional biochemical index and the sugar metabolic index as well as the serum levels of TXNIP, reduced glutathione (GSH), total superoxide dismutase (SOD), malondialdehyde (MDA), and tumor necrosis factor alpha (TNF-α). The correlation between TXNIP and NCV was also analyzed.Results: Compared with the NCVN group, the TXNIP and MDA values were significantly increased in the NCVA group (P < 0.05). Among the patients with T2DM, age, fasting glucose, SDBG, and TXNIP were risk factors for NCV abnormality, while vitamin D3 was a protective factor. After adjusting for related confounding factors, TXNIP was significantly correlated with NCV (P < 0.05). Among the patients with T2DM, TXNIP was an independent risk factor for left ulnar motor conduction velocity (MCV), right ulnar MCV, left median MCV, and right median MCV. TNF-α was identified as a positive influencing factor for serum TXNIP, while serum TXNIP was a positive factor for TNF-α and MDA (both P < 0.05).Conclusion: Serum TXNIP is related to NCV in T2DM patients. In combination with oxidative stress and inflammation, TXNIP may affect diabetic peripheral neuropathy (DPN).

A model to predict the probability of acute inflammatory demyelinating polyneuropathy

ObjectiveWe aimed to develop a model that can predict the probabilities of acute inflammatory demyelinating polyneuropathy (AIDP) based on nerve conduction studies (NCS) done within eight weeks. MethodsThe derivation cohort included 90 Malaysian GBS patients with two sets of NCS performed early (1–20days) and late (3–8 weeks). Potential predictors of AIDP were considered in univariate and multivariate logistic regression models to develop a predictive model. The model was externally validated in 102 Japanese GBS patients. ResultsMedian motor conduction velocity (MCV), ulnar distal motor latency (DML) and abnormal ulnar/normal sural pattern were independently associated with AIDP at both timepoints (median MCV: p = 0.038, p = 0.014; ulnar DML: p = 0.002, p = 0.003; sural sparing: p = 0.033, p = 0.009). There was good discrimination of AIDP (area under the curve (AUC) 0.86–0.89) and this was valid in the validation cohort (AUC 0.74–0.94). Scores ranged from 0 to 6, and corresponded to AIDP probabilities of 15–98% at early NCS and 6–100% at late NCS. ConclusionThe probabilities of AIDP could be reliably predicted based on median MCV, ulnar DML and ulnar/sural sparing pattern that were determined at early and late stages of GBS. SignificanceA simple and valid model was developed which can accurately predict the probability of AIDP.

A systematic review of randomized controlled trials of the Wenyang Huoxue method in treating diabetic peripheral neuropathy.

Objective:To assess the efficacy and safety of the Wenyang Huoxue method for patients with diabetic peripheral neuropathy.Methods:A systematic literature search was performed using 7 databases: PUBMED, EMBASE, the Chinese National Knowledge Infrastructure, Wanfang, Chinese BioMedical, and the VIP Chinese Science and Technique Journals. The publication time was from the start of each database up to November 2018. Review Manager 5.3 software was used for assessing potential bias, data synthesis, and the subgroup analysis. Begg and Egger tests were used to assess funnel plot symmetries using Stata 14.0 software. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) system was used to assess the quality of evidence.Results:A total of 22 trials involving 1835 participants were eligible. There were significant differences in a total effective rate between the Wenyang Huoxue method combined with Western medicine and Western medicine alone (RR = 1.33, 95% CI 1.26–1.41; P < .00001). As for the sensory conduction velocity (SCV) of the peroneal nerve, the Wenyang Huoxue method combined with Western medicine compared with Western medicine alone had a significant increase (weighted mean difference [WMD] = 5.00, 95% CI 3.42–6.57; P < .00001). Also, the Wenyang Huoxue method combined with Western medicine had significant increases in motor conduction velocity (MCV) of the peroneal nerve (WMD = 4.48, 95% CI 3.78–5.19; P < .00001), tibial nerve SCV (WMD = 3.47, 95% CI 2.66–4.28; P < .00001), tibial nerve MCV (4.87, 95% CI 3.21–6.53; P < .00001), median nerve SCV (WMD = 3.78, 95% CI 3.07–4.50; P < .00001), and median nerve MCV (WMD = 4.50, 95% CI 3.40–5.59; P < .00001). However, the effect of the Wenyang Huoxue method on fasting blood glucose, 2-h postprandial blood glucose, and glycosylated hemoglobin was not statistically significant. Egger's test results showed that there was no publication bias (P = .0008), but the trim and filling method showed steady results. An influence analysis showed that no single study affected the overall result. The GRADE quality of the evidence was low to moderate across the different outcomes.Conclusion:Despite of the apparently positive findings, the quality of GRADE is not high, suggesting that the Wenyang Huoxue method can improve nerve conduction velocity to a certain extent, but more rigorous literature is needed to support this evidence.

Hidden hearing loss in patients with Charcot-Marie-Tooth disease type 1A

The aim of this study was to investigate hidden hearing loss in patients with Charcot-Marie-Tooth disease type 1 A (CMT1A), a common inherited demyelinating neuropathy. By using pure-tone audiometry, 43 patients with CMT1A and 60 healthy controls with normal sound detection abilities were enrolled. Speech perception in quiet and noisy backgrounds, spectral ripple discrimination (SRD), and temporal modulation detection (TMD) were measured. Although CMT1A patients and healthy controls had similar pure-tone thresholds and speech perception scores in a quiet background, CMT1A patients had significantly (p < 0.05) decreased speech perception ability in a noisy background compared to controls. CMT1A patients showed significantly decreased temporal and spectral resolution (both p < 0.05). Also, auditory temporal processing of CMT1A patients was correlated with speech perception in a noisy background (r = 0.447, p < 0.01) and median motor conduction velocity (r = 0.335, p < 0.05). Therefore, we assumed that demyelination of auditory nerve in CMT1A causes defective cochlear neurotransmission, which reduces temporal resolution and speech perception in a noisy background. Because the temporal resolution test was well correlated with the degree of demyelination in auditory and peripheral motor nerves, temporal resolution testing could be performed as an additional marker for CMT1A.

Change in peripheral nervous conduction velocity in patients with occupational chronic mercury poisoning and related influencing factors

Objective: To investigate the change in peripheral nervous conduction velocity in patients with occupational chronic mercury poisoning and related influencing factors. Methods: From February 2011 to December 2014, urinary mercury examination and neural electromyography were performed for 104 patients with occupational chronic mercury poisoning. The data on age, type of work, working years of mercury exposure, and past medical history were collected, and peripheral nervous conduction velocity and its correlation with age, working years of mercury exposure, and urinary mercury concentration were analyzed. Results: All the 104 patients with occupational chronic mercury poisoning had a mean of 45.37±9.82 years, median (P(25), P(75)) working years of 7 (3, 11) , and a median (P(25), P(75)) urinary mercury concentration of 88.50 (56.25, 163.03) μg/g Cr. The major clinical manifestations of peripheral nerve injuries were numbness of extremities (20.2%) , hypopselaphesia/hypalgesia or hyperpselaphesia/hyperalgesia (9.6%) , and bone/muscle pain in the extremities (6.7%) . Neural electromyography showed an increase in denervation potential (fibrillation potential or positive sharp wave) and a detection rate of abnormal peripheral nervous conduction velocity as high as 65.4%. The patients with an older age and more working years had a higher incidence rate of abnormal sensory conduction velocity of the ulnar nerve. There were significant reductions in motor and sensory conduction velocities of the median nerve, motor and sensory conduction velocities of the ulnar nerve, motor conduction velocity of the common peroneal nerve, and the sensory conduction velocity of the superficial peroneal nerve (P<0.05) , with the increase in urinary mercury concentration. Conclusion: Patients with occupational mercury poisoning have a high rate of abnormal neural electromyographic findings, which can be used as an important method for early identification of chronic peripheral nerve injuries induced by mercury poisoning. The degree of peripheral nerve injuries increases with the increasing time of mercury exposure and urinary mercury concentration.

Do Electrodiagnostic Variables Correlate with Functional Outcomes in Carpal Tunnel Syndrome?

Background: The most common entrapment neuropathy seen in electrodiagnostic (EDX) laboratories is carpal tunnel syndrome (CTS). The diagnostic value of EDX with regard to CTS is well-established, but EDX’s predictive value is unclear. To date, only one study has attempted to establish a relationship between EDX findings and a patient’s clinical status pre- and post-treatment, and there was no significant relationship found. Objective: To establish a relationship between EDX variables and clinical severity assessment with Disabilities of the Arm, Shoulder, and Hand (DASH) scores at a single point in time and over a period of time. Methods: The study was a prospective single group cohort. 41 patients referred to an EDX clinic with suspected diagnoses of CTS were enrolled. Patients underwent EDX studies and completed DASH questionnaires at initial and follow-up visits at 8-month to 12-month intervals. Data collected included median sensory, mixed, and motor latencies, amplitudes, conduction velocities, and needle electromyography (EMG). Correlation coefficients were determined between EDX data variables and severity assessment (independent variables) and patients’ DASH questionnaire measures (dependent variables) at initial and follow-up assessments. Results: Change in DASH score over time positively correlated with left distal median motor latency (DMML) decrement and right transcarpal median sensory conduction block and negatively correlated with left median sensory nerve action potential (SNAP) amplitude decrement percentage, right needle EMG motor unit morphology abnormality, and right median forearm motor conduction velocity increment. The correlations observed are of unclear significance since the DASH scores themselves did not change significantly over time. Conclusions: Objective EDX data coupled with patient-reported outcome (PRO) measures such as the DASH score may be more meaningful in directing clinical care than either of them alone.

Electrophysiological and clinical comparison of local steroid injection by means of proximal versus distal approach in patients with mild and moderate carpal tunnel syndrome

Local corticosteroid injection is one of the treatment modalities for carpal tunnel syndrome. Symptomatic and electrophysiological improvement following local corticosteroid injection has been documented. The aim of the present study was to compare the effects of proximal and distal approaches of local steroid injection in patients with mild and moderate carpal tunnel syndrome on clinical scores and electrophysiological parameters at the end of 1 month following injection. A total of 30 patients were included and randomly assigned into one of the two groups based on the local steroid injection approach either by means of distal (group I) or by mean of proximal approach (group II). Clinical and electrophysiological examinations were carried out before and 1 month following the injection. There was a significant reduction in the pain and disability scores of the Boston Carpal Tunnel Questionnaire between the baseline and follow-up in both groups. Median motor nerve distal latency was statistically significantly reduced in both groups 1 month after the injection. Median motor conduction velocity and amplitude (amp) showed a statistically nonsignificant difference 1 month following the injection. Median sensory distal latency, amp, and conduction velocity showed statistically significant difference between the two groups. The average duration of the procedure in group I was 9.29 ± 0.76 s compared with 47.91 ± 9.66 s in group II. The average grade of pain expressed by the patients in group I was 1.97 ± 0.82 compared with 5.11 ± 0.67 in group II. Local corticosteroid injection at the carpal tunnel using the distal approach is associated with favorable clinical and electrophysiological results similar to those reported using the proximal approach. The distal approach is much less time consuming and more comfortable compared with the proximal approach.

HAND WEAKNESS IN CHARCOT-MARIE-TOOTH DISEASE 1X

There have been suggestions from previous studies that patients with Charcot-Marie-Tooth disease (CMT) have weaker dominant hand muscles. Since all studies to date have included a heterogeneous group of CMT...

Nerve conduction studies in Charcot–Marie–Tooth disease in a cohort from Turkey

In the demyelinating form of Charcot-Marie-Tooth disease, median motor conduction velocity (MCV) was noted to be around 20 m/s in peripheral myelin protein 22 (PMP22) duplications, in contrast to higher MCVs in connexin 32 gene (Cx32) mutations and lower MCVs in the demyelinating form of myelin protein zero gene (MPZ) mutations.Nerve conduction studies were performed in 64 families with both common and rare mutations.Mean MCV of the median nerve was 20 ± 5 m/s in PMP22 duplications, 34 ± 6 m/s in Cx32 mutations, 20 ± 9 m/s in KIAA1985 (SH3TC2) mutations, and 11 ± 8 m/s in MPZ mutations. Conduction was generally uniform; however, conduction blocks were present in 1 patient each with the MPZ mutation and PMP22 duplication, both with unusual phenotypes.Our results confirm those of the other investigators. Electrophysiological results of the rare KIAA1985 (SH3TC2) mutation reveal that their MCVs span a broad range and that conduction is uniform.

Hand weakness in Charcot-Marie-Tooth disease 1X

There have been suggestions from previous studies that patients with Charcot–Marie–Tooth disease (CMT) have weaker dominant hand muscles. Since all studies to date have included a heterogeneous group of CMT patients we decided to analyse hand strength in 43 patients with CMT1X. We recorded handedness and the MRC scores for the first dorsal interosseous and abductor pollicis brevis muscles, median and ulnar nerve compound motor action potentials and conduction velocities in dominant and non-dominant hands. Twenty-two CMT1X patients (51%) had a weaker dominant hand; none had a stronger dominant hand. Mean MRC scores were significantly higher for first dorsal interosseous and abductor pollicis brevis in non-dominant hands compared to dominant hands. Median nerve compound motor action potentials were significantly reduced in dominant compared to non-dominant hands. We conclude that the dominant hand is weaker than the non-dominant hand in patients with CMT1X.

Influence of Age and the Severity of Median Nerve Compression on Forearm Median Motor Conduction Velocity in Carpal Tunnel Syndrome

Forearm median motor conduction velocity (FMCV) is reduced in carpal tunnel syndrome (CTS). The aim of this study was to investigate the association of FMCV with age and severity of median nerve compression. Forearm median motor conduction velocity and median nerve motor distal latencies were measured in 312 CTS hands. Forearm median motor conduction velocity correlated negatively with age. This correlation persisted in the subgroups of hands with severe and less severe CTS. Forearm median motor conduction velocity correlated negatively with the degree of compression (as measured by median nerve motor distal latencies). This correlation persisted in subgroup of hands with severe CTS but not in less severe ones. Multiple regression analysis comparing the influence of age and median nerve motor distal latencies on FMCV showed higher standardized coefficients (beta) value for age than for median nerve motor distal latencies, suggesting a greater influence for age. The beta value for age is higher in severe group than in less severe group, suggesting that age has higher influence on FMCV in severe group. The degree of compression influences FMCV in hands with severe CTS but not in hands with less severe CTS. This difference in severe and less severe CTS may be because of the differences in the underlying pathophysiological processes in the 2 entities.

Influence of age and the severity of median nerve compression on forearm median motor conduction velocity in carpal tunnel syndrome.

Forearm median motor conduction velocity (FMCV) is reduced in carpal tunnel syndrome (CTS). The aim of this study was to investigate the association of FMCV with age and severity of median nerve compression. Forearm median motor conduction velocity and median nerve motor distal latencies were measured in 312 CTS hands. Forearm median motor conduction velocity correlated negatively with age. This correlation persisted in the subgroups of hands with severe and less severe CTS. Forearm median motor conduction velocity correlated negatively with the degree of compression (as measured by median nerve motor distal latencies). This correlation persisted in subgroup of hands with severe CTS but not in less severe ones. Multiple regression analysis comparing the influence of age and median nerve motor distal latencies on FMCV showed higher standardized coefficients (beta) value for age than for median nerve motor distal latencies, suggesting a greater influence for age. The beta value for age is higher in severe group than in less severe group, suggesting that age has higher influence on FMCV in severe group. The degree of compression influences FMCV in hands with severe CTS but not in hands with less severe CTS. This difference in severe and less severe CTS may be because of the differences in the underlying pathophysiological processes in the 2 entities.

Nerve conduction studies in Charcot–Marie–Tooth disease in a cohort from Turkey

In the demyelinating form of Charcot-Marie-Tooth disease, median motor conduction velocity (MCV) was noted to be around 20 m/s in peripheral myelin protein 22 (PMP22) duplications, in contrast to higher MCVs in connexin 32 gene (Cx32) mutations and lower MCVs in the demyelinating form of myelin protein zero gene (MPZ) mutations. Nerve conduction studies were performed in 64 families with both common and rare mutations. Mean MCV of the median nerve was 20 ± 5 m/s in PMP22 duplications, 34 ± 6 m/s in Cx32 mutations, 20 ± 9 m/s in KIAA1985 (SH3TC2) mutations, and 11 ± 8 m/s in MPZ mutations. Conduction was generally uniform; however, conduction blocks were present in 1 patient each with the MPZ mutation and PMP22 duplication, both with unusual phenotypes. Our results confirm those of the other investigators. Electrophysiological results of the rare KIAA1985 (SH3TC2) mutation reveal that their MCVs span a broad range and that conduction is uniform.

Electrodiagnosis of Carpal Tunnel Syndrome: Which Transcarpal Conduction Technique Is Best?

Transcarpal conduction techniques are commonly used to be supplementary techniques to distal sensory and motor latencies (DSL and DML) in the electrodiagnosis of carpal tunnel syndrome (CTS). However, which transcarpal conduction techniques, or combination of techniques, are the most sensitive for the electrodiagnosis of CTS is unknown. To determine which transcarpal conduction technique is the most sensitive for the electrodiagnosis of CTS, we prospectively conduct this study. Study subjects were 100 patients with CTS and 50 controls. In addition to DSL and DML determinations, all subjects were evaluated using four transcarpal conduction techniques. These were (1) median wrist-palm sensory conduction time (W-Psen CT); (2) median wrist-palm mixed nerve conduction time (W-Pmix CT); (3) the difference of conduction time across wrist between median and ulnar nerves (W-Pmix M-U CT); and (4) median wrist-palm motor conduction velocity (W-Pmot CV). The sensitivities and specificities of these tests were compared. Ninety patients had one or more electrophysiologic abnormalities. The DSL and DML diagnostic sensitivities were 74% and 72%, respectively. Better sensitivities were obtained with W-Psen CT (82%), W-Pmot CV (81%), W-Pmix CT (78%), and W-Pmix M-U CT (79%). Compared between four transcarpal conduction techniques, there was no significant difference in sensitivity. Of 26 patients with CTS with normal DSL, additional electrophysiologic abnormalities were revealed with W-Psen CT (30.7%), W-Pmot CV (53.8%), W-Pmix CT (30.7%), or W-Pmix M-U CT (38.5%). When W-Pmot CV was compared with W-Psen CT and W-Pmot CV versus W-Pmix CT, calculated probabilities (P = 0.07) showed a clear trend toward statistical significance. Furthermore, of 20 patients with normal DSL and DML, five patients had abnormality for W-Psen CT, eight for W-Pmot CV, four for W-Pmix CT, and six for W-Pmix M-U CT. On the basis of the results, we concluded that the most simple and reliable transcarpal conduction for electrodiagnosis of CTS was W-Psen CT. The most sensitive technique was W-Pmot CV in subjects with normal DSL or with normal DSL and DML. Evaluation of transcarpal motor conduction affords a useful supplementary technique to W-Psen CT.